Most of the electricity generated in the United States requires hydrocarbon-based fuel sources such as coal, oil or natural gas. The burning of such fuels produces harmful emissions that are both difficult and expensive to either contain, or remove, from the exhaust gasses. Also, the transport of these fuels from point of origin, to point of processing (such as refining crude oil), to point of use not only requires the expenditure of additional energy, but is inefficient, costly, potentially hazardous and creates further harmful emissions. In addition, most sources of liquid hydrocarbon-based fuels used in the United States are located outside of the United States. The political environments of many producing areas, such as the Middle East, Venezuela, Russia and Nigeria have been unstable in recent history.
Nuclear power plants pose an alternative generating source to hydrocarbon fuels. However, nuclear power plants are expensive to build and pose security problems. Also, the disposal and storage of spent nuclear fuel is an expensive and a highly contentious problem. Public perception of nuclear power plants is largely negative.
Solar panels are still another alternative. At present, solar panels are high in cost, very low in efficiency and are unusable at night and on cloudy or stormy days. Wind power, while available, is also dependent on the weather as well as being inefficient and relatively expensive.
In contrast to solar and wind, the tides are highly regular, cycling once or twice each twenty-four hour period. Although the height of tides vary due to factors such as coastline geography, the lunar cycle, and to a lesser degree, the direction and velocity of the wind, tides are remarkably constant and continuously changing. In some areas of the world, the water level range may be as much as forty-four feet between high and low tide.
In the prior art, tides have been harnessed by opening and closing flood gates to impound a head of water. The impounded water drives turbines. Such schemes have been planned, if not actually used, in Passamaquoddy Bay between Maine and New Brunswick, Canada. The continuous opening and closing of the flood gates creates problems. Also, the efficiency is somewhat low because only part of the tidal rise and fall can be used. Marine life is adversely impacted as well.